Multicolored LED lighting method and apparatus

ABSTRACT

The systems and methods described herein relate to LED systems capable of generating light, such as for illumination or display purposes. The light-emitting LEDs may be controlled by a processor to alter the brightness and/or color of the generated light, e.g., by using pulse-width modulated signals. Thus, the resulting illumination may be controlled by a computer program to provide complex, predesigned patterns of light in virtually any environment.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to providing light of a selectablecolor using LEDs. More particularly, the present invention is a methodand apparatus for providing multicolored illumination. More particularlystill, the present invention is an apparatus for providing a computercontrolled multicolored illumination network capable of high performanceand rapid color selection and change.

[0002] It is well known that combining the projected light of one colorwith the projected light of another color will result in the creation ofa third color. It is also well known that the three most commonly usedprimary colors—red, blue and green—can be combined in differentproportions to generate almost any color in the visible spectrum. Thepresent invention takes advantage of these effects by combining theprojected light from at least two light emitting diodes (LEDs) ofdifferent primary colors.

[0003] Computer lighting networks are not new. U.S. Pat. No. 5,420,482,issued to Phares, describes one such network that uses different coloredLEDs to generate a selectable color. Phares is primarily for use as adisplay apparatus. However, the apparatus has several disadvantages andlimitations. First, each of the three color LEDs in Phares is poweredthrough a transistor biasing scheme in which the transistor base iscoupled to a respective latch register through biasing resistors. Thethree latches are all simultaneously connected to the same data lines onthe data bus. This means it is impossible in Phares to change all threeLED transistor biases independently and simultaneously. Also, biasing ofthe transistors is inefficient because power delivered to the LEDs issmaller than that dissipated in the biasing network. This makes thedevice poorly suited for efficient illumination applications. Thetransistor biasing used by Phares also makes it difficult, if notimpossible, to interchange groups of LEDs having different powerratings, and hence different intensity levels.

[0004] U.S. Pat. No. 4,845,481, issued to Havel, is directed to amulticolored display device. Havel addresses some, but not all of theswitching problems associated with Phares. Havel uses a pulse widthmodulated signal to provide current to respective LEDs at a particularduty cycle. However, no provision is made for precise and rapid controlover the colors emitted. As a stand alone unit, the apparatus in Havelsuggests away from network lighting, and therefore lacks any teaching asto how to implement a pulse width modulated computer lighting network.Further, Havel does not appreciate the use of LEDs beyond mere displays,such as for illumination.

[0005] U.S. Pat. No. 5,184,114, issued to Brown, shows an LED displaysystem. But Brown lacks any suggestion to use LEDs for illumination, orto use LEDs in a configurable computer network environment. U.S. Pat.No. 5,134,387, issued to Smith et al., directed to an LED matrixdisplay, contains similar problems. Its rudimentary current controlscheme severely limits the possible range of colors that can bedisplayed.

[0006] It is an object of the present invention to overcome thelimitations of the prior art by providing a high performance computercontrolled multicolored LED lighting network.

[0007] It is a further object of the present invention to provide aunique LED lighting network structure capable of both a linear chain ofnodes and a binary tree configuration.

[0008] It is still another object of the present invention to provide aunique heat-dissipating housing to contain the lighting units of thelighting network.

[0009] It is yet another object of the present invention to provide acurrent regulated LED lighting apparatus, wherein the apparatus containslighting modules each having its own maximum current rating and eachconveniently interchangeable with one another.

[0010] It is a still further object of the present invention to providea unique computer current-controlled LED lighting assembly for use as ageneral illumination device capable of emitting multiple colors in acontinuously programmable 24-bit spectrum.

[0011] It is yet a still further object of the present invention toprovide a unique flashlight, inclinometer, thermometer, generalenvironmental indicator and lightbulb, all utilizing the generalcomputer current-control principles of the present invention.

[0012] Other objects of the present invention will be apparent from thedetailed description below.

SUMMARY OF THE INVENTION

[0013] In brief, the invention herein comprises a pulse width modulatedcurrent control for an LED lighting assembly, where eachcurrent-controlled unit is uniquely addressable and capable of receivingillumination color information on a computer lighting network. In afurther embodiment, the invention includes a binary tree networkconfiguration of lighting units (nodes). In another embodiment, thepresent invention comprises a heat dissipating housing, made out of aheat-conductive material, for housing the lighting assembly. The heatdissipating housing contains two stacked circuit boards holdingrespectively the power module and the light module. The light module isadapted to be conveniently interchanged with other light modules havingprogrammable current and hence maximum light intensity, ratings. Otherembodiments of the present invention involve novel applications for thegeneral principles described herein.

DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a stylized electrical circuit schematic of the lightmodule of the present invention.

[0015]FIG. 2 is a stylized electrical circuit schematic of the powermodule of the present invention.

[0016]FIG. 3 is an exploded view of the housing of one of theembodiments of the present invention.

[0017]FIG. 4 is a plan view of the LED-containing side of the lightmodule of the present invention.

[0018]FIG. 5 is a plan view of the electrical connector side of thelight module of the present invention.

[0019]FIG. 6 is a plan view of the power terminal side of the powermodule of the present invention.

[0020]FIG. 7 is a plan view of the electrical connector side of thepower module of the present invention.

[0021]FIG. 8 is an exploded view of a flashlight assembly containing theLED lighting module of the present invention.

[0022]FIG. 9 is a control block diagram of the environmental indicatorof the present invention.

DETAILED DESCRIPTION

[0023] The structure and operation of a preferred embodiment will now bedescribed. It should be understood that many other ways of practicingthe inventions herein are available, and the embodiments describedherein are exemplary and not limiting. Turning to FIG. 1, shown is anelectrical schematic representation of a light module 100 of the presentinvention FIGS. 4 and 5 show the LED-containing side and the electricalconnector side of light module 100. Light module 100 is self-contained,and is configured to be a standard item interchangeable with anysimilarly constructed light module. Light module 100 contains a ten-pinelectrical connector 110 of the general type. In this embodiment, theconnector 110 contains male pins adapted to fit into a complementaryten-pin connector female assembly, to be described below. Pin 180 is thepower supply. A source of DC electrical potential enters module 100 onpin 180. Pin 180 is electrically connected to the anode end of lightemitting diode (LED) sets 120, 140 and 160 to establish a uniform highpotential on each anode end.

[0024] LED set 120 contains red LEDs, set 140 contains blue and set 160contains green, each obtainable from the Nichia America Corporation.These LEDs are primary colors, in the sense that such colors whencombined in preselected proportions can generate any color in thespectrum. While three primary colors is preferred, it will be understoodthat the present invention will function nearly as well with only twoprimary colors to generate any color in the spectrum. Likewise, whilethe different primary colors are arranged herein on sets of uniformlycolored LEDs, it will be appreciated that the same effect may beachieved with single LEDs containing multiple color-emittingsemiconductor dies. LED sets 120, 140 and 160 each preferably contains aserial/parallel array of LEDs in the manner described by Okuno in U.S.Pat. No. 4,298,869, incorporated herein by reference. In the presentembodiment, LED set 120 contains three parallel connected rows of ninered LEDs (not shown), and LED sets 140 and 160 each contain fiveparallel connected rows of five blue and green LEDs, respectively (notshown). It is understood by those in the art that, in general, each redLED drops the potential in the line by a lower amount than each blue orgreen LED, about 2.1 V, compared to 4.0 V, respectively, which accountsfor the different row lengths. This is because the number of LEDs ineach row is determined by the amount of voltage drop desired between theanode end at the power supply voltage and the cathode end of the lastLED in the row. Also, the parallel arrangement of rows is a fail-safemeasure that ensures that the light module 100 will still function evenif a single LED in a row fails, thus opening the electrical circuit inthat row. The cathode ends of the three parallel rows of nine red LEDsin LED set 120 are then connected in common, and go to pin 128 onconnector 110. Likewise, the cathode ends of the five parallel rows offive blue LEDs in LED set 140 are connected in common, and go to pin 148on connector 110. The cathode ends of the five parallel rows of fivegreen LEDs in LED set 160 are connected in common, and go to pin 168 onconnector 110. Finally, on light module 100, each LED set is associatedwith a programming resistor that combines with other components,described below, to program the maximum current through each set ofLEDs. Between pin 124 and 126 is resistor 122, 6.2 Ω. Between pin 144and 146 is resistor 142, 4.7 Ω. Between pin 164 and 166 is resistor 162,4.7 Ω. Resistor 122 programs maximum current through red LED set 120,resistor 142 programs maximum current through blue LED set 140, andresistor 162 programs maximum current through green LED set 160. Thevalues these resistors should take are determined empirically, based onthe desired maximum light intensity of each LED set. In the presentembodiment, the resistances above program red, blue and green currentsof 70, 50 and 50 μA, respectively.

[0025] With the electrical structure of light module 100 described,attention will now be given to the electrical structure of power module200, shown in FIG. 2. FIGS. 6 and 7 show the power terminal side andelectrical connector side of an embodiment of power module 200. Likelight module 100, power module 200 is self contained. Interconnectionwith male pin set 110 is achieved through complementary female pin set210. Pin 280 connects with pin 180 for supplying power, delivered to pin280 from supply 300. Supply 300 is shown as a functional block forsimplicity. In actuality, supply 300 can take numerous forms forgenerating a DC voltage. In the present embodiment, supply 300 provides24 Volts through a connection terminal (not shown), coupled to pin 280through transient protection capacitors (not shown) of the general type.It will be appreciated that supply 300 may also supply a DC voltageafter rectification and/or voltage transformation of an AC supply, asdescribed more fully in U.S. Pat. No. 4,298,869.

[0026] Also connected to pin connector 210 are three current programmingintegrated circuits, ICR 220, ICB 240 and ICG 260. Each of these is athree terminal adjustable regulator, preferably part number LM317B,available from the National Semiconductor Corporation, Santa Clara,Calif. The teachings of the LM317 datasheet are incorporated herein byreference. Each regulator contains an input terminal, an output terminaland an adjustment terminal, labeled I, O and A, respectively. Theregulators function to maintain a constant maximum current into theinput terminal and out of the output terminal. This maximum current ispre-programmed by setting a resistance between the output and theadjustment terminals. This is because the regulator will cause thevoltage at the input terminal to settle to whatever value is needed tocause 1.25 V to appear across the fixed current set resistor, thuscausing constant current to flow. Since each functions identically, onlyICR 220 will now be described. First, current enters the input terminalof ICR 220 from pin 228. Of course, pin 228 in the power module iscoupled to pin 128 in the light module, and receives current directlyfrom the cathode end of the red LED set 120. Since resistor 122 isordinarily disposed between the output and adjustment terminals of ICR220 through pins 224/124 and 226/126, resistor 122 programs the amountof current regulated by ICR 220. Eventually, the current output from theadjustment terminal of ICR 220 enters a Darlington driver. In this way,ICR 220 and associated resistor 122 program the maximum current throughred LED set 120. Similar results are achieved with ICB 240 and resistor142 for blue LED set 140, and with ICG 260 and resistor 162 for greenLED set 160.

[0027] The red, blue and green LED currents enter another integratedcircuit, IC1 380, at respective nodes 324, 344 and 364. IC1 380 ispreferably a high current/voltage Darlington driver, part no. DS2003available from the National Semiconductor Corporation, Santa Clara,Calif. IC1 380 is used as a current sink, and functions to switchcurrent between respective LED sets and ground 390. As described in theDS2003 datasheet, incorporated herein by reference, IC1 contains sixsets of Darlington transistors with appropriate on-board biasingresistors. As shown, nodes 324, 344 and 364 couple the current from therespective LED sets to three pairs of these Darlington transistors, inthe well known manner to take advantage of the fact that the currentrating of IC1 380 may be doubled by using pairs of Darlingtontransistors to sink respective currents. Each of the three on-boardDarlington pairs is used in the following manner as a switch. The baseof each Darlington pair is coupled to signal inputs 424, 444 and 464,respectively. Hence, input 424 is the signal input for switching currentthrough node 324, and thus the red LED set 120. Input 444 is the signalinput for switching current though node 344, and thus the blue LED set140. Input 464 is the signal input for switching current through node364, and thus the green LED set 160. Signal inputs 424, 444 and 464 arecoupled to respective signal outputs 434, 454 and 474 on microcontrollerIC2 400, as described below. In essence, when a high frequency squarewave is incident on a respective signal input, IC1 380 switches currentthrough a respective node with the identical frequency and duty cycle.Thus, in operation, the states of signal inputs 424, 444 and 464directly correlate with the opening and closing of the power circuitthrough respective LED sets 120, 140 and 160.

[0028] The structure and operation of microcontroller IC2 400 will nowbe described. Microcontroller IC2 400 is preferably a MICROCHIP brandPIC16C63, although almost any properly programmed microcontroller ormicroprocessor can perform the software functions described herein. Themain function of microcontroller IC2 400 is to convert numerical datareceived on serial Rx pin 520 into three independent high frequencysquare waves of uniform frequency but independent duty cycles on signaloutput pins 434, 454 and 474. The FIG. 2 representation ofmicrocontroller IC2 400 is partially stylized, in that persons of skillin the art will appreciate that certain of the twenty-eight standardpins have been omitted or combined for greatest clarity.

[0029] Microcontroller IC2 400 is powered through pin 450, which iscoupled to a 5 Volt source of DC power 700. Source 700 is preferablydriven from supply 300 through a coupling (not shown) that includes avoltage regulator (not shown). An exemplary voltage regulator is theLM340 3-terminal positive regulator, available from the NationalSemiconductor Corporation, Santa Clara, Calif. The teachings of theLM340 datasheet are hereby incorporated by reference. Those of skill inthe art will appreciate that most microcontrollers, and many otherindependently powered digital integrated circuits, are rated for no morethan a 5 Volt power source. The clock frequency of microcontroller IC2400 is set by crystal 480, coupled through appropriate pins. Pin 490 isthe microcontroller IC2 400 ground reference.

[0030] Switch 600 is a twelve position dip switch that may be alterablyand mechanically set to uniquely identify the microcontroller IC2 400.When individual ones of the twelve mechanical switches within dip switch600 are closed, a path is generated from corresponding pins 650 onmicrocontroller IC2 400 to ground 690. Twelve switches create 2¹²possible settings, allowing any microcontroller IC2 400 to take on oneof 4096 different IDs, or addresses. In the preferred embodiment, onlynine switches are actually used because the DMX-512 protocol, discussedbelow, is employed.

[0031] Once switch 600 is set, microcontroller IC2 400 “knows” itsunique address (“who am I”) and “listens” on serial line 520 for a datastream specifically addressed to it. A high speed network protocol,preferably a DMX protocol, is used to address network data to eachindividually addressed microcontroller IC2 400 from a central networkcontroller (not shown). The DMX protocol is described in a United StatesTheatre Technology, Inc. publication entitled “DMX512/1990 Digital DataTransmission Standard for Dimmers and Controllers,” incorporated hereinby reference. Basically, in the network protocol used herein, a centralcontroller (not shown) creates a stream of network data consisting ofsequential data packets. Each packet first contains a header, which ischecked for conformance to the standard and discarded, followed by astream of sequential bytes representing data for sequentially addresseddevices. For instance, if the data packet is intended for light numberfifteen, then fourteen bytes from the data stream will be discarded, andthe device will save byte number fifteen. If as in the preferredembodiment, more than one byte is needed, then the address is consideredto be a. starting address, and more than one byte is saved and utilized.Each byte corresponds to a decimal number 0 to 255, linearlyrepresenting the desired intensity from Off to Full. (For simplicity,details of the data packets such as headers and stop bits are omittedfrom this description, and will be well appreciated by those of skill inthe art.) This way, each of the three LED colors is assigned a discreteintensity value between 0 and 255. These respective intensity values arestored in respective registers within the memory of microcontroller IC2400 (not shown). Once the central controller exhausts all data packets,it starts over in a continuous refresh cycle. The refresh cycle isdefine by the standard to be a minimum of 1196 microseconds, and amaximum of 1 second.

[0032] Microcontroller IC2 400 is programmed continually to “listen” forits data stream. When microcontroller IC2 400 is “listening,” but beforeit detects a data packet intended for it, it is running a routinedesigned to create the square wave signal outputs on pins 434, 454 and474. The values in the color registers determine the duty cycle of thesquare wave. Since each register can take on a value from 0 to 255,these values create 256 possible different duty cycles in a linear rangefrom 0% to 100%. Since the square wave frequency is uniform anddetermined by the program running in the microcontroller IC2 400, thesedifferent discrete duty cycles represent variations in the width of thesquare wave pulses. This is known as pulse width modulation (PWM).

[0033] The PWM interrupt routine is implemented using a simple counter,incrementing from 0 to 255 in a cycle during each period of the squarewave output on pins 434, 454 and 474. When the counter rolls over tozero, all three signals are set high. Once the counter equals theregister value, signal output is changed to low. When microcontrollerIC2 400 receives new data, it freezes the counter, copies the new datato the working registers, compares the new register values with thecurrent count and updates the output pins accordingly, and then restartsthe counter exactly where it left off. Thus, intensity values may beupdated in the middle of the PWM cycle. Freezing the counter andsimultaneously updating the signal outputs has at least two advantages.First, it allows each lighting unit to quickly pulse/strobe as a strobelight does. Such strobing happens when the central controller sendsnetwork data having high intensity values alternately with network datahaving zero intensity values at a rapid rate. If one restarted thecounter without first updating the signal outputs, then the human eyewould be able to perceive the staggered deactivation of each individualcolor LED that is set at a different pulse width. This feature is not ofconcern in incandescent lights because of the integrating effectassociated with the heating and cooling cycle of the illuminationelement. LEDs, unlike incandescent elements, activate and deactivateessentially instantaneously in the present application. The secondadvantage is that one can “dim” the LEDs without the flickering thatwould otherwise occur if the counter were reset to zero. The centralcontroller can send a continuous dimming signal when it creates asequence of intensity values representing a uniform and proportionaldecrease in light intensity for each color LED. If one did not updatethe output signals before restarting the counter, there is a possibilitythat a single color LED will go through nearly two cycles withoutexperiencing the zero current state of its duty cycle. For instance,assume the red register is set at 4 and the counter is set at 3 when itis frozen. Here, the counter is frozen just before the “off” part of thePWM cycle is to occur for the red LEDs. Now assume that the network datachanges the value in the red register from 4 to 2 and the counter isrestarted without deactivating the output signal. Even though thecounter is greater than the intensity value in the red register, theoutput state is still “on”, meaning that maximum current is stillflowing through the red LEDs. Meanwhile, the blue and green LEDs willprobably turn off at their appropriate times in the PWM cycle. Thiswould be perceived by the human eye as a red flicker in the course ofdimming the color intensities. Freezing the counter and updating theoutput for the rest of the PWM cycle overcomes these disadvantages,ensuring the flicker does not occur.

[0034] The network interface for microcontroller IC2 400 will now bedescribed. Jacks 800 and 900 are standard RJ-8 network jacks. Jack 800is used as an input jack, and is shown for simplicity as having onlythree inputs: signal inputs 860, 870 and ground 850. Network data entersjack 800 and passes through signal inputs 860 and 870. These signalinputs are then coupled to IC3 500, which is an RS-485/RS-422differential bus repeater of the standard type, preferably a DS96177from the National Semiconductor Corporation, Santa Clara, Calif. Theteachings of the DS96177 datasheet are hereby incorporated by reference.The signal inputs 860, 870 enter IC3 500 at pins 560, 570. The datasignal is passed through from pin 510 to pin 520 on microcontroller IC2400. The same data signal is then returned from pin 540 on IC2 400 topin 530 on IC3 500. Jack 900 is used as an output jack and is shown forsimplicity as having only five outputs: signal outputs 960, 970, 980,990 and ground 950. Outputs 960 and 970 are split directly from inputlines 860 and 870, respectively. Outputs 980 and 990 come directly fromIC3 500 pins 580 and 590, respectively. It will be appreciated that theforegoing assembly enables two network nodes to be connected forreceiving the network data. Thus, a network may be constructed as adaisy chain, if only single nodes are strung together, or as a binarytree, if two nodes are attached to the output of each single node.

[0035] From the foregoing description, one can see that an addressablenetwork of LED illumination or display units can be constructed from acollection of power modules each connected to a respective light module.As long as at least two primary color LEDs are used, any illumination ordisplay color may be generated simply by preselecting the lightintensity that each color emits. Further, each color LED can emit lightat any of 255 different intensities, depending on the duty cycle of PWMsquare wave, with a full intensity pulse generated by passing maximumcurrent through the LED. Further still, the maximum intensity can beconveniently programmed simply by adjusting the ceiling for the maximumallowable current using programming resistances for the currentregulators residing on the light module. Light modules of differentmaximum current ratings may thereby be conveniently interchanged.

[0036] The foregoing embodiment may reside in any number of differenthousings. A preferred housing for an illumination unit is described.Turning now to FIG. 3, there is shown an exploded view of anillumination unit of the present invention comprising a substantiallycylindrical body section 10, a light module 20, a conductive sleeve 30,a power module 40, a second conductive sleeve 50, and an enclosure plate60. It is to be assumed here that the light module 20 and the powermodule 40 contain the electrical structure and software of light module100 and power module 200, described above. Screws 62, 64, 66, 68 allowthe entire apparatus to be mechanically connected. Body section 10,conductive sleeves 30 and 50 and enclosure plate 60 are preferably madefrom a material that conducts heat, most preferably aluminum. Bodysection 10 has an open end, a reflective interior portion and anillumination end, to which module 20 is mechanically affixed. Lightmodule 20 is disk shaped and has two sides. The illumination side (notshown) comprises a plurality of LEDs of different primary colors. Theconnection side holds an electrical connector male pin assembly 22. Boththe illumination side and the connection side are coated with aluminumsurfaces to better allow the conduction of heat outward from theplurality of LEDs to the body section 10. Likewise, power module 40 isdisk shaped and has every available surface covered with aluminum forthe same reason. Power module 40 has a connection side holding anelectrical connector female pin assembly 44 adapted to fit the pins fromassembly 22. Power module 40 has a power terminal side holding aterminal 42 for connection to a source of DC power. Any standard AC orDC jack may be used, as appropriate.

[0037] Interposed between light module 20 and power module 40 is aconductive aluminum sleeve 30, which substantially encloses the spacebetween modules 20 and 40. As shown, a disk-shaped enclosure plate 60and screws 62, 64, 66 and 68 seal all of the components together, andconductive sleeve 50 is thus interposed between enclosure plate 60 andpower module 40. Once sealed together as a unit, the illuminationapparatus may be connected to a data network as described above andmounted in any convenient manner to illuminate an area. In operation,preferably a light diffusing means will be inserted in body section 10to ensure that the LEDs on light module 20 appear to emit a singleuniform frequency of light.

[0038] From the foregoing, it will be appreciated that PWM currentcontrol of LEDs to produce multiple colors may be incorporated intocountless environments, with or without networks. For instance, FIG. 8shows a hand-held flashlight can be made to shine any conceivable colorusing an LED assembly of the present invention. The flashlight containsan external adjustment means 5, that may be for instance a set of threepotentiometers coupled to an appropriately programmed microcontrollerthrough respective A/D conversion means 15. Each potentiometer wouldcontrol the current duty cycle, and thus the illumination intensity, ofan individual color LED on LED board 25. With three settings eachcapable of generating a different byte from 0 to 255, acomputer-controlled flashlight may generate twenty-four bit color. Ofcourse, three individual potentiometers can be incorporated into asingle device, such as a track ball or joystick, so as to be operable asa single adjuster. Further, it is not necessary that the adjustmentmeans must be a potentiometer. For instance, a capacitive or resistivethumb plate may also be used to program the two or three registersnecessary to set the color. A non-hand held embodiment of the presentinvention may be used as an underwater swimming pool light. Since thepresent invention can operate at relatively low voltages and lowcurrent, it is uniquely suited for safe underwater operation.

[0039] Similarly, the present invention may be used as a generalindicator of any given environmental condition. FIG. 9 shows the generalfunctional block diagram for such an apparatus. Shown within FIG. 9 isalso an exemplary chart showing the duty cycles of the three color LEDsduring an exemplary period. As one example of an environmentalindicator, the power module can be coupled to an inclinometer. Theinclinometer measures general angular orientation with respect to theearth's center of gravity. The inclinometer's angle signal can beconverted through an A/D converter and coupled to the data inputs of themicrocontroller in the power module. The microcontroller can then beprogrammed to assign each discrete angular orientation a different colorthrough the use of a lookup table associating angles with LED colorregister values. The “color inclinometer” may be used for safety, suchas in airplane cockpits, or for novelty, such as to illuminate the sailson a sailboat that sways in the water. Another indicator use is toprovide an easily readable visual temperature indication. For example, adigital thermometer can be connected to provide the microcontroller atemperature reading. Each temperature will be associated with aparticular set of register values, and hence a particular color output.A plurality of such “color thermometers” can be located over a largespace, such as a storage freezer, to allow simple visual inspection oftemperature over three dimensions.

[0040] Another use of the present invention is as a lightbulb. Usingappropriate rectifier and voltage transformation means, the entire powerand light modules may be placed in an Edison-mount (screw-type)lightbulb housing. Each bulb can be programmed with particular registervalues to deliver a particular color bulb, including white. The currentregulator can be pre-programmed to give a desired current rating andthus preset light intensity. Naturally, the lightbulb will have atransparent or translucent section that allows the passage of light intothe ambient.

[0041] While the foregoing has been a detailed description of thepreferred embodiment of the invention, the claims which follow definemore freely the scope of invention to which applicant is entitled.Modifications or improvements which may not come within the explicitlanguage of the claims described in the preferred embodiments should betreated as within the scope of invention insofar as they are equivalentor otherwise consistent with the contribution over the prior art andsuch contribution is not to be limited to specific embodimentsdisclosed.

1. Light apparatus comprising: a power terminal; at least one LEDcoupled to the power terminal; a switch coupled to the at least one LED,the switch comprising an input responsive to an activation signal toenable flow of current through the switch; an addressable controllerhaving an alterable address, the controller coupled to the input and thecontroller generating the activation signal for a portion of a timingcycle; the addressable controller further comprising a network interfacethat receives data corresponding to the alterable address, the portionof the timing cycle responsive to the received data; a second LEDcoupled to the power terminal and the switch; the switch comprising asecond input corresponding to the second LED and responsive to a secondactivation signal; and the addressable controller generating the secondactivation signal for a second portion of the timing cycle, and furtherreceiving data from the network interface corresponding to the alterableaddress, the second portion of the timing cycle responsive to thereceived data.